Stabilized physical developments



United States Patent 3,251,692 STABILIZED PHYSICAL DEVELOPMENTS HendrikJonker and Comelis Johannes Dippel, both of Emmasingel, Eindhoven,Netherlands, assignors to North American Philips Company, Inc., NewYork, N.Y., a corporation of Delaware No Drawing. Application Oct. 2,1964, Ser. No. 405,644, which is a division of application Ser. No.845,098, Oct. 8, 1959, now Patent No. 3,157,502. Divided and thisapplication Apr. 5, 1965, Ser. No. 445,760

. 2 Claims. (CI. 96-66) This invention relates to developers used in thepurely physical developments of photographic images and to processesemploying such developers.

This application is a division of our copending application Serial No.405,644, filed October 2, 1964, which is in turn a division of ourapplication Serial'No. 845,098, filed October 8, 1959, now US. PatentNo. 3,157,502.

In the usual type of development employed in photography, the so-calledchemical development, the metal in the visual photographic image isobtained by the reduction of metal ions of the water insoluble metalcompound present in the latent image in the exposed light sensitivelayer.

The developing solution employed in chemical develop- .ment initiallydoes not contain any dissolved compounds of the visual image metal.However, after the chemical developer is used for a while it may containin solution ions of the visual image metal.

In the purely physical development the intensification or development ofthe latent image is carried out by treating the latent image with adeveloping solution which contains a water soluble reducible metalcompound and a photographic reducing agent.

In physical developing practically all of the metal in the resultantvisual image is formed by the selective reduction of metal ions orcomplex metals anions supplied by said water soluble metal compound.

The term photographic reducing agent is to be understood hereinto mean acompound which, in the dissolved state, is capable of reducing the saidmetal ions or complex metal anions into free metal and the activity ofwhich in the physical developer under the conditions otherwiseprevailing therein is accelerated by the presence of a photographiclatent image so as to obtain a sufficiently selective deposition ofmetal on this latent image.

The photographic reducers which may be used in physical development arefrequently similar to those which are also used in chemical development.

They often satisfy the formula wherein C represents a carbon atom, a andb each represent hydroxyl (OH) groups, amino groups or substituted aminogroups (NH NHR, NRR' wherein R and R are alkyl or aryl radicals groups),n is zero or an integer.

It is possible to distinguish three large classes of photographicreducing agents which correspond to the above general formula.

(1) That of the hydroquinone type: a andb both are OH groups. This classincludes, in addition to hydroquinone itself, inter alia: pyrocatechol,pyrogallol, gallic acid and ascorbic acid.

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(2) That of the aminophenol type: a is an OH-group and b is an aminogroup which is substituted or not substituted. This class includes interalia: oand p-aminophenol, p-methylaminophenol-sulphate (metol),p-hydroxyphenylglycine (Kodurol).

(3) That of the phenylenediam-ine type: a is an amino group or amono-substituted amino group, b is an amino group which is substitutedor non-substituted. This class includes inter alia: oandp-phenylenediamine and N,N- diethyl-p-phenylenediamine.

In addition, there are some further photographic reducing agents whichdo not satisfy the above-mentioned formula, such asl-phenyl-3-pyrazolidone (Phenidone) and several inorganic photographicreducing agents, such as ferrous, titanous and vanadous ions, which arecommonly used in the form of complex compounds, for example theferrous-oxalate complex.

In purely physical developers, only metal ions and complex metal anionsof metals which are more precious than copper i.e. mercury, silver,platinum, gold or palladium may be used in combination with photographicreducing agents. These metals in the instant application will behereinafter designated as precious metals. A physical developerfrequently used is, for example, a solution of silver nitrate in Waterto which hydroquinone and p-phenylenediamine have been added. Inaddition, some further sub stances are usually added to such adeveloper, which substances serve to increase the length of life or tocontrol the velocity of development. These are, for example, organicacids, buffer mixtures or substances which enter into reaction with theprecious metal salt to form thereby complex metal anions.

The purely physical development hitherto employed has disadvantageswhich has prevented its general introduction into the photographictechniques. These disadvantages are due to the fact that physicaldevelopers, in contradist-inction to chemical developers, are unstablesystems due to a homogeneous reaction being liable to occur in thesolution between the precious metal compound and the reducing agent inaddition to the heterogeneous reaction on the latent image, whereby thelatter is intensified, which homogeneous reaction then results in thespontaneous formationof metal germs in the solution and in thephotographic material outside of the latent image which germs formprecipitates. In addition, a spontaneous catalyzed reduction may occuron the wall of the developing vessel and this reduction likewise givesrise to unwanted loss of a metal. Once such metal germs havingspontaneously been formed, their growth will compete with the depositionof the metal on the latent image obtained by the reaction of light. Thisspontaneous formation of the metal precipitates, of course, also takesplace when the physical developer is not in use and this results infairly rapid deterioration of such developers While depositing metal andin considerable contamination of the vessel employed. Such developersare thus uneconomical in use.

The spontaneous formation of the metal germs and resultant formation ofprecipitates in the photographic material outside the latent imageobtained by illumination may give rise to unwanted fogging of theultimate photographic image. The spontaneous dissociation reaction inphysical developers is usually accomplished in a period of time which isnot very much longer than the time required for the development of themetal latentimage into a photographic visual metal image of desiredoptical density.

It is known that, in certain cases, it is possible to increase thelength of life of a purely physical developer, for example, by reducingthe temperature, by dilution, by decreasing the pH or by the addition ofthe oxidation product of the reducing agent. However, these steps causea corresponding increase in the time of development, thus rendering suchprocesses serviceable for the technique only in certain cases or incombination with additional steps. Such a step is, for example, toincrease the temperature of photographic material containing an amountof such a developer sufiicient for building up the image. Developersthus treated have sometimes been referred to as stabilized developers.However, they are not stabilized in the sense of the present inventionin which the spontaneous separation of the precious metal from thedeveloper is likewise materially decreased, but without at the same timeconsiderably retarding the velocity of development. The first-mentionedkind of increase of the length of life will be referred to hereinafteras inactivation and the relevant developers will be referred to asinactivated developers. If, on the other hand, as is frequentlydesirable, efforts are made to shorten the time of development in thepurely physical development, for example by increasing the temperature,by the use of higher concentrations of the reacting constituents, or byincreasing the pH, this is always at the expense of the length of lifeof the developer, while the possibility of fogging considerablyincreases, in certain cases even to an extent such that the selectivityof the precipitation of metal on the photographic metal latent graphicprocess based on the photo-sensitivity of silver halide, the chemicaldevelopment has been preferred. However, there are cases that chemicaldevelopment is impossible and hence physical development is the onlypossibility of intensifying the photographic latent images, since theimage-producing metal, in contradistinction to the chemical development,is not yet present as a nonsoluble compound in the area of the image.However, also in these cases in which chemical development is possible,physical development is sometimes desirable in view of the betterquality of the image, for example, in con nection with the highresolving power that can be obtained with it.

It is therefore a principal object of this invention to provide purelyphysical developers which are stable, that is, in which there is littleor no precipitation of metal from the precious metal compound in thedeveloper outside of the latent photographic image.

Another object of this invention is to provide purely physicaldevelopers which do not cause fogging.

These and other objects of the invention will be apparent from thedescription that follows.

According to this invention it has been found that the precipitation ofthe precious metal from the developer outside of the latent imagebecause of the homogeneous reaction between the photographic reducingagent and the precious metal compound of the developer can be eliminatedto a very large extent by the addition of one or more suitable ionicsurface active agents or surfactants to the developer. As a result ofthe addition of these surfactants the life of the developer is increasedat least 50% and in one case is 10,000 times that of the correspondingunstabilized developer.

The use of these ionic surfactants is based on the different behavioursof the ionic surfactants in physical development, so far as the metalprecipitates spontaneously formed in the developer and the visual metalimage in the photographic material are concerned. Such a selectivity is,of course, essential to proper action of the dethe metal precipitatesspontaneously formed, without.

nevertheless affecting the growth of the photographic metal visual imagein the exposed layer in a manner which is of practical importance.

The process of the invention may be carried out with all thosephotographic materialsin which a physically developable metal latentimage may be obtained directly or indirectly by the action of light.These photographic materials include first of all those materials whichcontain a photosensitive compound, the light reaction product of whichas such already behaves as a physically developable photographic metallatent image, for example materials containing silver halide as thephotosensitive compound. In addition, they include all those photographic materials which contain a photosensitive com- 7 pound'the lightreaction product of which as such is not physically developable, but bya secondary reaction may be converted or react into a physicallydevelopable photographic metal latent image. If the light reactionproduct is a metal compound, this secondary reaction consists inisolating metal particles from the metal compound, as is the case, forexample, in the photographic process in which use is made ofthe-photosensitivity of the so-called Eder solution and in which thelight reaction product is mercurous chloride. Numerous photosensitivecompounds are also known, the light reaction product of which in asecondary reaction may react in the presence of moisture withmercurous-ions or with silver-ions while forming physically developablelatent mercury images and latent silver images respectively. Suchphotosensitive compounds, such as aromatic diazonium compounds,diazosulphonates and diazocyanides and inorganic complex compounds, areused in a large number of processes for the manufacture of photographicimages.

Surfactants or surface-active substances, that is to say, substanceswhich are adsorbed at the boundary surface of two phases, are usuallyorganic compounds having amphi-. pathic properties. Their molecule orion contains one or more hydrophobic and one or more lipophilic groups,which are bonded together either directly or via, for ex ample, anester, ether or amide bond. The hydrophobic groups are, for example,aliphatic carbon chains having from 8 to 18 carbon atoms with a verysmall afiinity to the medium (water), in contradistinction to thehydrophilic groups which have a great affinity to water. The latter aretherefore sometimes referred to as solubilising or polar groups. Thesemay be, for example, sulphonate or pyridinium groups.

The surfactants may chemically be divided into two classes:

(a) The ionic surfactants, the hydrophilic group of which carries thecharge and which thus occur in the form of an anion, a cation or azwitterion. Reference is then made to anion-active, cation-active andamphoteric surfactants, respectively.

(b) Thenon-ionic surfactants, the hydrophilic group of which isnon-ionisable.

During the establishment of the present invention, it has been foundthat a favourable technical effect in the sense previously described canbe obtained only when use is made of surfactants of the first-mentionedcategory that is the ionic surfactants. The non-ionic surfactants arethus unserviceable as development stabilizers. The serviceablesurfactants chiefly belong to the classes of the cation-active,anion-active and amphoteric micellproducing surfactants and to the classof the cation-active macro-molecular surfactants.

In chemical developers, too, surfactants are sometimes used, for exampleof the quaternary ammonium type compounds. These may considerably speedup the develbathed for a short time, for example, in a 0.2% solution oflauryl-pyridinium-p-toluenesulphonate. The problem of which the presentinvention provides a solution in the physical development does notexist, however, in the chemical development and the effect of thesurfactants is therefore of quite a different nature.

As previously mentioned, physical developers may have greatly differingcompositions; they may react in an acid, neutral or alkaline reactionand they may contain different compounds of precious metals,photographic reducing agents of different kinds and many sorts ofauxiliary materials. Consequently, it will be evident that the choice ofthe ionic surfactants used for obtaining stabilization of developmentcannot be arbitrary. For example, those few ionic surfactants whichproduce in one way or another a precipitation with one of theconstituents of the physical developer cannot be used. Also there may beinsuflicient activity by the surfactant because of the low dissociationof the surfactant at the pH of the developer concerned.

In order to determine whether a given ionic surfactant is serviceable asa physical developer stabilizer under the conditions which prevail inthe physical developer chosen, the following test may be carried out.

By means of a sensitometer wedge, identical photographic metal latentimages are manufactured on two foils of one of the photographicmaterials defined above. In covered developing vessels one of thesefoils is developed in a developer containing the surfactant to be tested(A), the other foil being developed in the corresponding developer fromwhich this surfactant is omitted (-B). The two foils are developed aslong as is necessary for obtaining a predominantly neutral-gray copy ofthe wedge in developer B. In the event of the length of life ofdeveloper B being so short as to be incapable of developing into oneneutral-grey copy, the development is stopped when the activity of thedeveloper has ceased; After the development of the first two foils hasbeen terminated, new latent image foils identical with thefirst-mentioned are introduced some more times into the two developersat given intervals, the period of which may naturally be varied as afunction of the length of life of the developers. The lengths of life ofthe two developers are thus approximately determined, that is to say,the times which elapse between the moment when the two developers wereprepared and the moments when their developing power has disappearedalmost completely. This test has at the most a semi-quantitativecharacter, since the spontaneous formation of the metal precipitate innon-stabilized developers is naturally not reproducible with greataccuracy. In order to avoid wrong conclusions which might result fromthe said fluctuations, one sets as a criterion of activity that thelength of life of developer A with respect to that of developer B mustbe increased at least by 50%.

During this test it is necessary to ensure that the total amount ofimage metal which is consumed for building up the image in all thecopies of the wedge developed in one and the same developing bath, isnot more than of the initial potential supply of metal of this bath.

It is not possible generally to indicate the limits of the effectiverange of concentration of the surfactants. Most of the surfactantscommercially sold are technical products which usually consist of amixture of homologues which possess the same hydrophilic group and henceare not clearly defined chemically. Otherwise these technical productsare, on the whole, quite serviceable without further purification,insofar as they do not show unwanted reactions in the physical developersuch as formation of a deposit. However, during the establishment of theinvention, it has been found that the number of carbon atoms of thelyophilic group influences the lower limit of activity when startingfrom pure, well defined compounds. Thus, for example, for a givenphysical developers it was found that for octylamine acetate this limitexists at a concentration of about 0.1 mol, for decylamine acetate at aconcentration of 0.03 molar and with dodecylamine acetate at aconcentration of 0.003 molar.

These results indicate that the stabilization effect of the surfactantsmay be related to micelle format-ion by the hydrophilic ions of thesurfactants at or about the small precious spontaneous metal germs fromthe precious metal compound thus preventing the germs from growing largeenough to precipitate out of the developer solution.

With increasing concentration of the surfactant, the

stabilizing effect in certain cases increases, then reaches a maximumand finally disappears completely. The latter is frequently accompaniedby flocculation of the surfactant, in which event the activityfrequently returns to an increased extent, if the fiocculated surfactantis solubilised with another ionic surfactant of the same charge or witha non-ionic surfactant. In other cases, however, a decline in activityupon increasing concentration of the surfactant could not be determined.It is not yet quite clear how all these phenomena must be interpreted.With reference to the sensitometer wedge test described supra, it ispossible in all cases to determine the most active concentration orconcentrations of the surfactant empirically.

During the experiments carried out in formulating this invention it wasfound by micro-electrophoretic measurements on the physical developersthat the surfactants acted upon the electrophoretic charge of theprecious metal germs. In the absence of the surfactants it was foundthat these precious metal germs had a charge depending to a large extenton the other ingredients in the developer.

,Thus it was found that the electrophoretic charge of the spontaneoussilver germs was distinctly negative in a metol-citric acid-silvernitrate developer and distinctly positive in a corresponding p-phenylenediamine-citric acid-silver nitrate developer. In corresponding alkalinedevelopers in which sodium sulphite was employed in addition the chargeon silver germ in both cases was found to be negative. The spontaneouslyformed germs of mercury were however, found to be positive in ahydroquinone, nitric acid, mercurous nitrate developer.

The surfactants act to increase the existing charge of the preciousmetal germs or to provide a new strong charge of opposite polarity onthe precious metal germ depending on whether cation or anion-activesurfactants are employed and whether the charge on the precious metalgerm is the same or opposite to that of the hydrophilic ion released bythe surfactant. By thus effecting the electrophoretic behaviour of thespontaneously formed precious metal germs in the physical developers thegrowth of these germs into sizes large enough to precipitate out of thesolution is prevented.

The action of the hydrophilic ions on the charge of spontaneous preciousmetal germs involves probably the formation of micelles which as statedbefore prevents the growth of these germs. A strong positive charge ofthe germs will prevent the approach of positive metal ions, whereas astrong negative charge may prevent transmission of electrons to thegerms and approach of negative complex metal ions. Consequently, incertain cases, a hydrophilic ion of one type of charge and, in othercases, one of the other type of charge, but frequently hydrophilic ionsof both types of charge result in a stabilizing effect in a physicaldeveloper. However, the photographic test above described always givesan answer to the question whether a given stabilizer is effective incertain kind of developer.

Nevertheless, it remains a surprising fact that the photographic metallatent image is not acted upon in the same manner as are the gremsspontaneously formed, in other words, that any appreciable decrease inthe velocity of development does not occur. Evidently, the position issuch that formation of micelles does not occur in the latent image andthat micelles formed outside latent image cannot enter it.

It has been found that most effective stabilization of the physicaldeveloper is ensured,'at least if the surfactant chosen does not becomeinactive due to reaction with one of the constituents of the developer,for example due to formation of a precipitate, if the surfactant ischosen to be such that the charge of the surface-active ion is oppositeto the electrophoretic charge of the precious metal germs formedspontaneously in the corresponding physical developer from which thesurfactant has been omitted and if the concentration of the surfactantis sufiicient so as to be capable of giving the spontaneous metal germsthe charge of surface-active ion.

A very good stabilizing effect may be obtained in physical developmentby means of acid reacting developers containing soluble silver compoundsor mercury compounds if the reducing agent employed is a compound of thehydroquinone type and the stabilizer is an alkylaryl sulphonate derivedfrom diphenyl.

Finally, physical gold developers may best be stabilized by means of thesame alkylaryl sulphonates which are derivatives of diphenyl.

8 EXAMPLES The specified formulas are included in the accompanyingtable.

I. A superficially saponified film of cellulose acetate was sensitizedby impregnating for 2 minutes with an aqueous solution containing 0.15gram mole of the sodium salt of o-methoxy-benzenediazosulphonic acid andAs previously mentioned, a given surfactant may sometimes show aconsiderably smaller stabilizing effect than could be expected due toits being flocculated under the conditions which prevail in the physicaldeveloper or due to its having itself unduly low solubility. In thiscase, the activity of the surfactant may be considerably increased bysolubilization. This maybe effected by means of another ionic surfactantof the same charge type or by means of a non-ionic surfactant.

A process is also known for obtaining metallic images in photographicmaterial by purely physical development of photographic metal latentimages, the photographic material being developed in the form of a stackof sheets in a physical developer which may, be inactivated, if desired,and which contains an amount of metal salt not more than about threetimes as much as suflices for building up the visual images. Accordingto the in- .vention, by the use of surfactants in the developers, muchmore beautiful results, less fogging and less contamination of thesheets due to finely-divided metal lossely deposited on them isobtained.

In combination with known steps by which the purely physical developmentis used in a continuous process, the invention imparts to the developerproperties rendering it even much attractive for practical use.

It is possible to carry out a developing process in which the developingliquid is continuously supplied from two separate supply solutions whichare stable in themselves. The invention may then successfully be used byadding a development stabilizer to at least one solution, so that betterresults are obtained and the process is accomplished more economically.

If a certain amount of photographic materials is physically developedseveral times in succession in a given amount of developer which isstabilized and possibly inactivated, the present invention also permitsof regenerating this developing liquid at will by adding metal salt oran aqueous solution thereof which may be provided with a stabilizer.Thev process of regenerating the developer may, of course, also becarried out continuously.

In addition, the known continuous process in which the photographicmaterial is caused to absorb an amount of inactivated developer at leastsufiicient for building up the images and in which the development isaccomplished substantially outside this supply, may be considerablyimproved by the use of the invention, since by means of stabilizers itis possible to prepare developer solutions which are durable for a muchlonger time than are the corresponding non-stabilized solutions andwhich nevertheless exhibit a reasonable developing activity.

The invention will now be explained in detail with reference to a numberof examples.

0.1 gram mole of cadmium acetate per liter, followed by wiping off anddrying. A piece of this film was exposed to the light of a mercury lampbehind a sensitometer wedge and subsequently treated with an aqueoussolution containing 0.005 gram mole of mercuous nitrate and 0.01 molofnitric acid per liter, resulting in a mercury germ image being formed(the so-called germ image foil). After the formation of the germ image,the foil was rinsed in distilled water. Astrip of the germ image foilwas physically developed for 10 minutes in a fresh solution of 0.5 g. ofmetal, 2 g. of citric acid and 0.2 g. of silver nitrate in g. ofdistilled water. The silver germs spontaneously formed in this solutionwere found to have a negative electrophoretic charge.

Another strip of the same germ image foil was developed for the sameperiod in a fresh solution which, in addition to the said constituents,also contained 0.02 g. of the cation-active surfactant Sapamine KW."This is the methyl sulphate of monostearylamido-ethylene-trimethyl-amine(Formula I). It was determined by electrophoretic means that. the germsformed spontaneously in the solution had a very distinct positivecharge. With certain intervals, which in this case were about 30minutes, new strips of germ image foils identical with thefirst-mentioned were introduced into the two-developing solutions anddeveloped therein for 10 minutes.

This procedure was continued until the developing power of each solutionhad disappeared almost completely, while taking care that in total notmore than about 10% of the silver potentially present in each of thedevelopers at the beginning of the test was used for building up theimage. The stabilized developing solution became inactive in a period oftime which was three times as long (the stabilization factor) as that inwhich the developer without the stabilizer became inactive. A delay inthe development was not established at all in this and the followingexamples of stabilized physical developers, unless special statementsare made to the contrary.

Instead of using the above-mentioned photosensitive material, it isalternatively possible in this and the corresponding subsequent examplesto utilize similar materials obtained by impregnation of regeneratedcellulose film or superficially saponified cellulose-ester film withsolutions of other aromatic diazosulphonates such, for example, as thesodium salt of p-methoxyor p-ethoxybenzene diazosulphonic acid, thesodium salt of chloro- 2-methyl-4 benzenediazosulphonic acid-1, and thesodium dimethoxy-3,4 salt of benzenediazosulphonic acid-1, or

with solutions of other photosensitive compounds from cal' developmenttook place for 8 minutes in solutions containing per 100 g. of distilledwater:

(a) 0.33 g. of potassium gold chloride 1.3 g. of oxalic acid (b) as aand, in addition, 0.2

g. of Aresklene-400 (Formula II) The length of life of developer b wasat least twice as long as that of developer a.

Table Formula Trade Name Source 1 [C 1sHa7fi-NCzH4N (CHa)s] (504C113)Sapamiue KW Ciba.

(C4Ho): II CsHrCe 0H Aresklene 400 Monsanto Chem. Co. (SOaNB)! III(CsH;NH-C QH;:)X (X=Cl or Br) Flxanol C Lilgllfg and 00. Imperial Chem.

' v NCH,

IV CH3(CH,),,-C

N CH;

For Amine 0, n=l6 M01. weight=355 Amine O Amine s, 11:16 Mol. welght=360Amine s )Almse Chem- R is a substituent having a comparatively lowmolecular weight.

NCHg.NHO3 V 0 1E530 Amine 220 nitrate Uralon Carbide and Carbon orp.NCH1 CHg-CHgOH VI CUHEafi-NCjHAN(C:H5)z-CHZC 0 0H Sapamine A Clba.

/0Hr-CH7CHI-N(CH1CH1OH)1 VII--. C1sHa1N Ethoduomeen T/m Armour and Co.

CHr-CH OH vnr.--- c.r1.-(:.H.{ S6553 }Aresket s00 Monsanto Chem. 00.

IX CH (CH;)1.C=(f(CH:)1CH1SO;Na Lissapol O Imp. Chem. Ind.

or CH:(CH2)1CH CH-(CH:)7-*CH OH S0,Na

While we have described our invention in connection with specificembodiments and applications, other modifications thereof will bereadily apparent to those skilled in this art without departing from thespirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A stabilized photographic physical developer comprising an aqueoussolution of a water soluble gold salt reducible to metallic gold, aphotographic reducing agent for reducing said gold salt to gold and asan anionic surfactant an alkylaryl sulfonate containing a diphenylmoiety, said surfactant being present in an amount sufficient toincrease the life of the developer at least 50% when compared to thelife of an identical developer without said surfactant.

References Cited by the Examiner UNITED STATES PATENTS 3,157,502 Il/1964 Ionker et a1. 96-49 NORMAN G. TORCHIN, Primary Examiner.

2. A STABILIZED PHOTOGRAPHIC PHYSICAL DEVELOPER COMPRISING AN AQUEOUSSOLUTION OF A WATER SOLUBLE GOLD SALT REDUCIBLE TO METALLIC GOLD, APHOTOGRAPHIC REDUCING AGENT FOR REDUCIN SAID GOLD SALT TO GOLD AND AS ANANIONIC SURFACTANT A DIBUTYL-O-PHENYLPHENOL SODIUM DISULPHONATE, SAIDSURFACTANT BEING PRESENT IN AN AMOUNT SUFFICIENT TO INCREASE THE LIFE OFTHE DEVELOPER AT LEAST 50% WHEN COMPARED TO THE LIFE OF AN IDENTICALDEVELOPER WITHOUT SAID SURFACTANT.